Keywords: human body posture; Spinal health; The chair form; Comfort; Relationship between 

1 human spine healthy 

1.1 the body posture 

Different from what most people think, sedentary than standing more tired. Sat on a seat when the burden of human lumbar spine will gradually increase, according to research shows that 80% of body weight are human lumbar to 4 to 5 day, too much sitting (that is, what people call the static strain) will bring great harm to human body. But due to long time of sitting discomfort or seat back discomfort, most people will choose to cross your legs, humpback, arch the back of the human body health damage, for a long time to keep this kind of posture is bound to cause disease of the spine. 

1.2 human spine physiological characteristics 

Spine is the life of the supporting role backbone, it is more than just a bone, it is around him in the muscle, ligament, nerves, blood vessels and other soft tissue together constitute the support girder of the body. We should correctly understand the spine for human health plays an important role. 

Vertebrae and iliac crest is the hardware of the spine. 12, 7 of cervical vertebra, thoracic vertebra lumbar 5, 5, sacral vertebral coccygeal vertebra 4, 33 vertebrae. With the minimum of cervical vertebra, sacral vertebral the thick, area for a third of cervical vertebra, thoracic vertebra area at one 6, with half lumbar area. 

Maintain health posture of seat largely depends on the health of the spine, lumbar spine into micro thrust forward state is healthy natural curve, by this time the whole lumbar spine is present health status, if it is rendered or other state, the spine is the direction of the morbid bending, then human spine rendered unhealthy state. The main physiological characteristics of health sitting position is the normal nature of the lumbar curve radian, back muscles are in a state of relaxation, this not only ensure the human spine curve of S type curve to keep healthy, and to ensure the load is not very big muscles. So in the long run is in the office of the state of the staff to reduce the pressure of the spine to the harm done by the body. 

2 back form and comfort 

2.1 market research 

Office chair now tend to be more ergonomic curve of the chair, but the curve is also varied, the curve of the different have different feelings to the human body, according to the measurement of the existing office chair, articles to heng Lin of the chairs industry in a detailed research and analysis of the existing office chair, at the same time online access to a lot of office furniture's official website and some office chair of newspapers and magazines about to consult relevant literature research. 

2.2 office chair back form factors 

The influencing factors of office chairs back morphological characteristics can be from two aspects to discuss - side and looking down, these two aspects to explore the morphological characteristics of back. Looking down into the waist of arc and back arc, foil side into the waist height, the Angle of back of the chair, the back side profile curve radian, waist, waist is prominent. (as shown) 

Form to the back of the chair can be formed, these factors determine the shape of the back of the chair on the market also has hundreds of thousands of form combination, constitute a variety of forms the back of the chair. Different form the back of the chair is very big to the influence that the human spine. 

2.3 office chair back form comfort test method 

Against the back of the chair form comfort can use method of body pressure distribution test instrument and subjective evaluation method to evaluate different comfort in the form of the back of the chair, according to the study, can from the average pressure, maximum pressure, and explore the comfort in the form of average pressure gradient on the back of the chair. 

3 human spine with office chair back form the relationship between the comfort 

3.1 form the back of the chair for the influence of human spine 

Office chair that appeared on the market at present basically all emerged as S type curve shape form the back of the chair, so back waist prominent place can give the body the waist support to ensure the health of human spine. Because the contact area is larger, the back and the back of the chair of the chair of the form to a large extent determines the shape of the spine to human body. So a reasonable back form is essential to the health of human spine. 

3.2 the human spine and office chair seat comfort form hypothesis is put forward 

Comfortable sitting posture is not necessarily a good posture, for spine has a problem, they will find a relative to their relatively comfortable sitting posture, for them, this position is only to conform to their current unhealthy spine form, that is bad for the healthy development of the spine in turn will aggravate the damage to the spine of the displacement and deformation of the spine. For healthy people hypothesis is put forward, the relationship between the spine and the back of the chair form in the human body healthy spine s-shaped stay relaxed at the same time, the body curve presents the state of nature, the small of the back muscles are in a state of relaxation, can maintain the normal circulation of blood, can achieve a comfortable state at this time, the small of the back with the reasonable support and comply with the health of human spine form at the same time. So, for healthy people, according to the human body the best curve to the back of the chair design makes the body depend on the back of the chair can present the best condition, which can ensure comfortable and can satisfy the spine health, so the back of the chair form for human comfort and the influence of human spine health, there is a certain correlation theory experiment needs further research and discussion. 

4 conclusion 

Form the back of the chair of the article is based on the morphology of human spine to carries on the discussion, most of the research at home and abroad are for the office chair comfort study, morphological characteristics and health sitting position for the seat of the study is relatively small, the back is to the human body the waist, back and neck to provide reasonable support, is the human body vertebra in sitting state keep natural curve, alleviate human lower back muscle fatigue, for human health have a vital role, the article has carried on the preliminary discussion to this aspect. 

reference 

[1] rong-rong Chen. Based on maintaining a healthy posture work chair design research [D]. Zhejiang university, 2007. 

[2] dan-dan zhang. Office chairs in the design of the man-machine engineering application [D]. Beijing forestry university, 2008. 

[3] Yi Xiqiong. Based on health posture desk staff function size optimization research [D]. Nanjing forestry university, 2010, 6. 

[4] hai-bo Yang. Health office chair design based on ergonomics research [D]. Jinan university. 

[5] giudice lc. Sofa chair of the human body comfort research [D]. Nanjing forestry university, 2008, 6. 

[6] Sankou Keikaku, Co., ltd. A Zen as for better sitting posture Faculty of Psychological Science [J]. Journal of Japan: Hiroshima International University. 

Author introduction: Jia Xuxia (1990 -), female, hebei zhangjiakou, work units: nanjing forestry university, officers: graduate school, research direction, industrial design engineering.